The invention is directed to a cellulose acetate anti-adhesion wound pad or dressing, and in particular to a cellulose acetate anti-adhesion pad having a low level of siloxane finishing agent applied thereto. The pad has use in the medical arts area for application to wounds, particularly burns.
Numerous injuries, and particularly burns, require the application of some type of pad, gauze, cloth, dressing or similar covering (herein collectively called a xe2x80x9cdressingxe2x80x9d) to protect the wound while it is healing. Wounds, especially burns, sometimes have difficulty in healing and are frequently prone to infection because natural protective skin barriers are disrupted and are slow in repairing themselves. The most commonly used dressing material has been cotton because it is both inexpensive and readily available. However, as those who have used cotton dressings are aware, they tend to stick to the injured area, even when the surface of the area is covered with a lubricant such as petroleum jelly (xe2x80x9cpetrolatumxe2x80x9d) or similar substance, or a medicinal which contains a lubricant. Developments in the medical arts have resulted in some improvements in medical dressings, two of which are represented by Johnson and Johnson""s ADAPCTIC(trademark) brand non-adherent dressings and the Curity(copyright) brand TELFA(copyright) sterile pads sold by Kendall-Futuro Company. The ADAPTIC(trademark) brand dressing was found to consist of a cellulose acetate pad which has been soaked in petrolatum or similar substance to impart anti-adhesion properties. While the petrolatum reduces adhesion to a wound, it""s use results in a pad that is greasy and messy to handle compared to a pad without petrolatum. The TELFA(copyright) dressing consists of a polyethylene terephthalate (PET) shell and a caustic washed cotton insert, the anti-adhesion properties being imparted by the PET shell.
Another dressing is disclosed in China Patent No. CN 87 1 01823 A, published Aug. 31, 1988, to Tie Han et al. This Chinese patent describes a xe2x80x9cMedicinal Anti-Adhesive Dressingxe2x80x9d prepared using plain cellulose acetate to make a spun and woven gauze, or a nonwoven fabric having a weight of 50-80 g/m2. No additional information is given concerning treatment of the cellulose acetate material before, during or after preparation of the dressing. The dressing did not contain a biostat nor was use of a biostat suggested.
United States patents disclosing the use of cellulosic materials and siloxane materials in wound dressing include:
U.S. Pat. No. 5,372,739 to B. Shriram which describes fibers, including cellulose acetate fibers, having polyethylene glycol fatty acids thereon to reduce adhesion;
U.S. Pat. No. 4,984,570 to Langen et al. which describes a wound dressing having a cellulose acetate absorbent pad and a hydrophobic man-made fiber covering over the pad which covering is in contact with the wound;
U.S. Pat. No. 4,546,027 to Holvoet which describes the use of a nonwoven corrugated fabric for medical and surgical compresses, which compresses include the use of plastic reinforced cellulose fibers;
U.S. Pat. No. 5,635,201 to Fabo which describes the use of a curable siloxane material coated on a carrier surface and heat cured to form a siloxane gel; and
U.S. Pat. No. 5,685,832 to Chen et al. which describes a wound dressing comprising a woven cellulose acetate substrate and a partial solvent thereon, which dressing releases, in a controlled manner, acetic acid to act as a therapeutic agent.
U.S. Pat. No. 3,285,245 to Eldridge et al. which describes an absorbent wound dressing having an absorbent backing and a non-absorbent facing.
These dressing, while having various qualities which may reduce adhesion or provide other benefits, incorporate lubricants and/or fluids or fluid releasing agents, and use fibers other than cellulose acetate to provide non-adhesion properties.
Adhesive dressings and methods of preparing adhesive dressings are well known in the art as exemplified by U.S. Pat. No. 4,595,001, and patent references cited therein, to Potter (a surgical dressing which carries an adhesive layer for securing a dressing to a body), all of whose teachings are incorporated herein by reference.
While the above dressings represent improvements in reducing dressing adhesion to wounds, further improvements in the field is highly desirous. In particular, an improved dressing of cellulose acetate would useful in the medical arts because cellulose acetate is both chemotactic for attracting white blood cells and hydrophilic. The white cell chemotactic property of cellulose acetate fibers is desirable in a wound dressing because white blood cells aid in fighting infection. The hydrophilic property is desirable because it aids in removing excess fluids which may ooze from the surface of a wound during the healing process. Accordingly, the present invention is directed to providing such improved dressing.
It is an object of the invention to provide a wound dressing made of cellulose acetate which has improved non-adhesion characteristics.
It is a further object of the invention to provide a wound dressing made of cellulose acetate and a low level of a siloxane finishing agent, which dressing has improved non-adhesion characteristics.
It is an object of the invention to provide a self-adhesive bandage having a wound dressing pad attached thereto, which pad is made of cellulose acetate with or without a low level of a siloxane finishing agent, and which pad has improved non-adhesion characteristics.
It is an additional object of the invention to provide a biostat containing wound dressing and/or self-adhesive bandage having a wound dressing attached thereto, which dressing is comprised in part or wholly of cellulose acetate, and has a low level of a siloxane finishing agent applied thereto; and which dressing has improved non-adhesion characteristics.
The invention is directed to a wound dressing which does not adhere to a wound surface or which has improved non-adhesion characteristics relative to the wound dressings known to the art. In the one embodiment, the invention comprises a woven or non-woven cellulose acetate dressing. In a preferred embodiment, the invention comprises a non-woven cellulose acetate web, and a particularly preferred nonwoven dressing comprises a spunlace material having a weight of about 20 to about 90 g/m2 (grams per square meter). These embodiments can further comprise such additional substances as low levels of siloxane materials to finish the dressing or the fibers used to make the dressing and additionally impart further adhesion-reduction characteristics; and anti-bilogics such as bactericides and fungicides which can be incorporated into the cellulose acetate before if is formed into a filament for use in producing the dressing or such anti-biologics incorporated into a fiber which can be used in conjunction with cellulose acetate fibers to produce the dressing.
In another embodiment, the invention is directed to an article of manufacture comprising an adhesive strip having an adhesive on one side thereof and a wound dressing adhering to a portion of the adhesive side of said strip, wherein said wound dressing comprises one or a plurality of layers of a fabric comprising cellulose acetate fibers, biostat-containing cellulose acetate fibers having a biostat content of about 1% to about 5%, and a siloxane in the amount of about 0.01% to about 0.0001%; wherein the amount of biostat-containing fibers in the dressing is from about 1% to about 100% of the total fiber in the dressing.
The term xe2x80x9canti-biologicxe2x80x9d or xe2x80x9cbiostatxe2x80x9d, and variations thereof, as used herein means any substance which has an effect on a biological organism, and in particular means bactericides, antibiotics, fungicides, herbicides, antimicrobials and similar substances which effect biological organisms, both animal and plant.
The term xe2x80x9cdressingxe2x80x9d as used herein means any material applied to protect, cushion, cover, and generally guard a wound from either further injury or from any desirable contacts. The material may be in any form such as a pad, gauze, cloth, sheet, or similar form as night be used in the medical arts. The dressing may be used by itself or in conjunction with a medicinal or other substance applied thereto or contained therein, and may comprise multiple layers of the cellulose acetate materials of which the dressing is made.
The terms xe2x80x9cnon-stick,xe2x80x9d xe2x80x9cno-stick,xe2x80x9d xe2x80x9canti-adherent,xe2x80x9d xe2x80x9cnon-adherentxe2x80x9d, xe2x80x9canti-adhesionxe2x80x9d and variations thereof, and similar terms, may be used interchangeably to signify a dressing which either does not stick or adhere to a wound, or which exhibits a reduced tendency to stick or adhere to a wound relative to other dressings.
The dressing may be made of either a woven or a nonwoven cellulose acetate; nonwoven being preferred. Further, the dressing may be made of cellulose acetate alone or in combination with another filament or fiber suitable for use in medical dressings, including polyesters, polyolefins, polyamides and cotton; polyesters being preferred.
All percentages herein are weight percentages unless specified otherwise.
General Preparative Methods
The cellulose acetate containing dressing of the invention may be either a woven or nonwoven material, nonwoven being preferred. The spinning process used to produce a cellulose acetate dressing can be either dry spinning or wet spinning as those terms are understood by one skilled in the art. A description of cellulose acetate filaments and fibers (hereafter collectively called xe2x80x9cfibersxe2x80x9d), and the materials and processes used to make such fibers, can be found in the xe2x80x9cEncyclopedia of Chemical Technology, 4th Ed.xe2x80x9d (Wiley-Interscience, John Wiley and Sons, New York), Vol. 10, pages 204-253 (nonwoven fabrics), 598-624 (cellulose esters) and 696-726 (regenerated cellulosics), and are well known to those skilled in the art.
The process used to incorporate anti-biologics into a fiber is well known in the art as exemplified by U.S. Pat. Nos. 3,959,556 and 4,343,853 to Morrison which describe incorporating an antimicrobial agent into a thermoplastic resin to produce a fiber having the antimicrobial intimately mixed with the resin. Cellulose acetate is a thermoplastic substance.
Woven fabrics can be prepared using cellulose acetate fibers by conventional weaving procedures known to those skilled in the art. Such techniques can be used to produce either a cellulose acetate (only) fabric or a fabric comprising cellulose acetate and a second fiber having an anti-biologic intimately mixed with the fiber resin.
Nonwoven fabrics can be prepared using cellulose acetate fibers by conventional nonwoven techniques known to those skilled in the art. In the preferred embodiment of the invention the nonwoven fabric is prepared according to the spunlace method. The spunlace method can be used to produce either a cellulose acetate (only) fabric or a fabric comprising cellulose acetate and a second fiber having an anti-biologic intimately mixed with the fiber. In the preferred embodiment the anti-biologic containing fiber is cellulose acetate and the anti-biologic containing fiber is present in the fabric in an amount of greater than zero pecent to 100% of the total fiber of the fabric.
The fibers used to produce woven or nonwoven fabric are made using spinnerets having 50 to about 250 openings therein for producing filaments of about 1 to about 50 denier per filament (dpf), with 1-5 dpf being preferred. Heavier dpf materials are used when multiple xe2x80x9clayersxe2x80x9d are desired in a nonwoven fabric, for example, for strength imparted by a layer of heavier fibers, or when it is desired to give any fabric more xe2x80x9cbody.xe2x80x9d The fabrics, and particularly the spunlace fabric, are produced in a weight range of about 20 to about 90 g/m2. After fabric forming, the fabric is then needled or punched to yield a fabric having from about 10 to about 200 openings per square centimeter. Alternatively, the fabric may be used as formed and not punched or needled to form openings. Subsequent to fabric forming and needling, the fabric may under go optional additional treatments such as washings. In preferred embodiments of the invention, the fabric was washed and treated with a siloxane containing solution comprising 2.27 kilograms (Kg) of 70% Sentry NF30 and 30% Nuwet 500 (both from Witco Chemicals, Greenwich, Conn., USA) in about 226 liters of deionized or distilled water (5 lbs per 60 gallons). Those skilled in the art are familiar with the foregoing siloxane materials and the invention hereby teaches that similar silicone materials from other sources can be substituted. Siloxane treatment time was in the range of 10-30 minutes, and with about 15 minutes being a typical treatment time. Following siloxane treatment the fabric was optionally water washed to remove excess silicone and dried The amount of siloxane on the fabric after washing, if any, and drying is from about 0.01% to about 0.0001%. The fabric may then be folded, cut and otherwise processed and packaged for sale to the end user. Fabric was sterilized by any sterilization method known in the art, for example, by gamma irradiation whereby 27-34 KGy was delivered. When applied to wounds, a dressing may consist of one or more layers of the fabric of the invention. Typically, one to twenty layers maybe use, the exact number being determined by the nature and/or severity of the wound.